Greg, the fact that you have not paid yet gives you the leverage that you need.
If this guy knows his stuff, then you can tell him to fix it or not be paid.
Maybe now it is time to consider whether you want to tell this guy to take a hike and find someone who knows what they are doing. By this, I mean, don't pay the guy at all, or give some cents on the dollar. I have no idea if your guy is good or not, but the pictues look wrong to me.
